The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
A variety of electric motors commonly include on-winding motor protectors, such as line break automatic reset control devices. Such protectors are connected in series with the motor windings, and are typically designed to track winding temperatures and respond to changes in line current to provide protection against overload conditions.
The manner in which on-winding motor protectors are connected to motor windings typically depends on the motor size and/or type. For example, in small dishwasher motors using stranded winding wire, the winding wire is sometimes coupled directly to the motor protector via a splice terminal. One end of the splice terminal is crimped to the stranded winding wire, and the other end of the splice terminal is crimped to a pin of the motor protector.
In contrast, hermetic motors for air conditioning, refrigeration and other applications generally require more robust connections to motor protectors due to the higher currents involved in such applications. Therefore, motor protectors for hermetic motors are commonly supplied by their manufacturers with a lead wire welded to each of the one or more steel pins, and another lead wire (common) welded to the motor protector housing (also referred to as the protector shell or dome). The lead wires are typically stranded (versus solid) wire and have a heavy braided insulation such as DMD (Dacron-Mylar-Dacron) insulation. The lead wires are usually coupled to the steel pins and housing of a motor protector using weld nuggets and resistance welding. The length, wire size and strip length of the lead wires can usually be selected as desired for a particular application when ordering the motor protectors. The motor protectors are integrated into electric motors by coupling the other ends of the lead wires (opposite the ends welded to the motor protector) in series with the motor windings or, in the case of a common lead wire, to a cluster block for the hermetic motor.
As recognized by the present inventors, such use of lead wires in hermetic motors introduces two potential points of failure in the winding connections, and can increase manufacturing costs due to the additional steps of attaching the lead wires to the winding wires and to the motor protector.